Image-guided Lymphadanectomy in AMIGO

Inclusion Criteria: * Signed written informed consent before any trial related procedure is undertaken that is not part of the standard patient management * Subjects aged ≥ 18 years. Selected patients must have a confirmed or suspected diagnosis of disease in the abdomen or retroperitoneum, with scheduled confirmatory surgical biopsy. * Subjects must have had a CT, PET examination or MR examination of acceptable quality at Brigham and Women's Hospital within the prior month Exclusion Criteria: * Severely impaired renal function with an EGFR \< 30 mL/min/body surface area * Evidence of any significant, uncontrolled comorbid condition that could affect compliance with the protocol or interpretation of the results, which is to be judged at the discretion of the PI * History of hypersensitivity or other contraindication to contrast media * Contraindication to general anesthesia * Pregnancy